英文药名: Carnitor (Levocarnitine)

中文药名: 左卡尼汀

药品名称
通用名称：左卡尼汀注射液
英文名称：Levocarnitine
成份: 左卡尼汀
【规格】5ml：1g 　　
【适应症】适用于慢性肾衰长期血透病人因继发性肉碱缺乏产生的一系列并发症状，临床表现如心肌病、骨骼肌病、心率失常、高脂血症，以及低血压和透析中肌痉挛等。 　　
【用法用量】每次血透后推荐起始剂量是10～20mg/Kg，溶于5～10ml注射水中，2～3分钟1次静脉推注，血浆祖卡尼汀波谷浓度低于正常（40-50μmol/L）立即开始治疗，在治疗第3或第4周时调整剂量（如在血透后5mg/Kg）。 　　
【不良反应】主要为一过性的恶心和呕吐、身体出现特殊气味、恶心和胃炎不常发生，由于引起这些反应的病理复杂，很难估测这些反应的发生率。口服或静脉注射左卡尼汀可引起癫痫发作，不论先前是否有癫痫病史、先前有癫痫发作的患者，可诱发癫痫或使癫痫加重。
在一项慢性血透患者双盲、安慰剂对照试验中，出现的不良反应（不考虑因果关系，仅报道发生率≥5%的反应）主要有：
1.全身系统：胸痛、感冒症状、头痛、注射部位反应、疼痛等；
2.心血管系统：心血管异常、高血压、低血压、心动过速等；
3.消化系统：腹泻、消化不良、恶心、呕吐等；
4.内分泌系统：甲状腺异常等；
5.血液淋巴系统：贫血等；
6.代谢系统：高钙血症、高钾血症、血容量增多症等；
7.神经系统：头晕、失眠、压抑等；
8.呼吸系统：咳嗽、咽喉炎、鼻炎等；
9.皮肤：瘙痒、皮疹；
10.泌尿系统：肾功能异常等。 　　
【禁忌症】对本品过敏者禁用。 　　
【注意事项】在肠胃外治疗前，建议先测定血浆卡尼汀水平，并建议每周和每月监测，监测内容包括血生化，生命体征，血浆卡尼汀浓度（血浆游离卡尼汀水平为35～60mmol/L）和全身状况。输液药品在使用前务必仔细观察有无异常和变色。本品在0.9%氯化钠注射液或乳酸盐林格注射液250mg/500ml到4200mg/500ml，放置在室温25℃于PVC塑料袋中24小时内稳定。药代动力学和临床研究表明，用左卡尼汀治疗血液透析的终末期肾脏病（ESRD）患者，可以提高血浆中左卡尼汀的浓度。 　　
【孕妇及哺乳期妇女用药】虽动物实验不能证明左卡尼汀的生殖毒性，但在孕妇尚未进行合适和对照的研究，动物实验结果与人可能有一定差异，除非临床必须使用时孕妇才使用本药。目前不清楚该药是否通过乳汁排泄，因为许多药都可以通过乳汁排泄，因此哺乳期是否可用此药或停用，须权衡对母亲的利弊。 　　
【儿童用药】见用法用量 　　
【老年用药】在老人未进行年龄与卡尼汀作用相互关系的合适的研究，但预计不存在限制本药在老人使用的特殊问题。 　　
【药物相互作用】根据临床潜在的意义：接受丙戊酸的患者需增加左卡尼汀的用量。 　　
【药物过量】还没有过量左卡尼汀引起毒性的报道。口服左卡尼汀可以很容易通过血透消除，口服左卡尼汀在老鼠的LD50是19.2g/kg，静脉是5.4g/kg。大剂量左卡尼汀可引起腹泻。 　　
【药理毒理】左卡尼汀是哺乳动物能量代谢中需要的体内天然物质，其主要功能是促进脂类代谢。在缺氧、缺血时，脂酰-CoA堆积，线粒体内的长链脂酰卡尼汀也堆积，游离卡尼汀因大量消耗而减低。缺血缺氧导致ATP水平下降，细胞膜和亚细胞膜通透性升高，堆积的脂酰-CoA可致酸中毒，离子紊乱，细胞自溶死亡。足够量的游离卡尼汀可以使堆积的脂酰-CoA进入线粒体内，减少其对腺嘌呤核苷酸转位酶的抑制，使氧化磷酸化得以顺利进行。左卡尼汀是肌肉细胞尤其是心肌细胞的主要能量来源，脑、肾等许多组织器官亦主要靠脂肪酸氧化供能。卡尼汀还能增加还原型烟酰胺腺嘌呤二核苷酸（NADH）细胞色素C还原酶、细胞色素氧化酶的活性、加速ATP的产生，参与某些药物的解毒作用。对于各种组织缺血缺氧，左卡尼汀通过增加能量产生而提高组织器官的供能。

【药代动力学】按20mg/kg的剂量，在3分钟内缓慢静脉注射后，血浆左卡尼汀符合二室模型。单次静脉管给药，在0～24小时内，大约76%左卡尼汀经尿排出。不计内源性左卡尼汀，血浆左卡尼汀的平均分布半衰期不0.585小时，平均终末清除半衰期为17.4小时，总的人体清除率平均为4.0L/小时，本品不与血浆蛋白或蛋白结合，主要代谢产物为三甲胺-N-氧化物和3H-r-丁酸甜菜碱，约有58%～65%由尿和粪排泄。
临床研究
【功效主治】 适用于慢性肾衰长期血透病人因继发肉碱缺乏产生的一系列并发症状，临床表现如心肌病、骨骼肌病、心律失常、高脂血症，以及低血压和透析中肌痉挛等。
【化学成分】 左卡尼汀 　　
【药理作用】 药理作用：左卡尼汀是哺乳动物能量代谢中需要的体内天然物质，其主要功能是促进脂类代谢。在缺氧、缺血时，脂酰-CoA堆积，线粒体内的长链脂酰卡尼汀也堆积，游离卡尼汀因大量消耗而减低。缺血缺氧导致ATP水平下降，细胞膜和亚细胞膜通透性升高，堆积的脂酰-CoA可致膜结构改变，膜相崩解而导致细胞死亡。另外，缺氧时以糖无氧酵解为主，脂肪酸等堆积导致酸中毒，离子紊乱，细胞自溶死亡。足够量的游离卡尼汀可使堆积的脂酰-CoA进入线粒体内，减少其对腺嘌呤核苷酸转位酶的抑制，使氧化磷酸化得以顺利进行。左卡尼汀是肌肉细胞尤其是心肌细胞的主要能量来源，脑、肾等许多组织器官亦主要靠脂肪酸氧化供能。卡尼汀还能增加NADH细胞色素C还原酶、细胞色素氧化酶的活性、加速ATP的产生，参与某些药物的解毒作用。对于各种组织缺血缺氧，左卡尼汀通过增加能量产生而提高组织器官的供能 　　
【药物相互作用】 根据临床潜在的意义，接受丙戊酸的患者需增加左卡尼汀的用量。 　　
【不良反应】 主要为一过性的恶心和呕吐，身体出现特殊气味、恶心和胃炎不常发生，由于引起这些反应的病理复杂，很难估测这些反应得发生率。口服或静脉注射左卡尼汀引起癫痫发作，不论先前是否有癫痫病史，先前有癫痫发作的患者，可诱发癫痫或使癫痫加重。
在一项慢性血透患者双盲、安慰剂对照试验中，出现的不良反应（不考虑因果关系，仅报道发生率≥5％的反应）主要有： 　　
1 全身系统：胸痛、感冒症状、头痛、注射部位反应、疼痛等。 　　
2 心血管系统：心血管异常、高血压、低血压、心动过速等。 　　
3 消化系统：腹泻、消化不良、恶心、呕吐等。 　　
4 内分泌系统：甲状腺异常等。 　　
5 血液淋巴系统：贫血等。 　　
6 代谢系统：高钙血症、高钾血症、血容量增多症等。 　　
7 神经系统：头晕、失眠、压抑等。 　　
8 呼吸系统：咳嗽、咽喉炎、鼻炎等。 　　
9 皮肤：瘙痒、皮症。 　　
10 泌尿系统：肾功能异常等。 　　
【禁忌症】 对本品过敏者禁用。

DESCRIPTION
CARNITOR® (levocarnitine) is a carrier molecule in the transport of long-chain fatty acids across the inner mitochondrial membrane.

The chemical name of levocarnitine is 3-carboxy-2( R )-hydroxy-N,N,N-trimethyl-1-propanaminium, inner salt. Levocarnitine is a white crystalline, hygroscopic powder. It is readily soluble in water, hot alcohol, and insoluble in acetone. The specific rotation of levocarnitine is between -29° and -32°. Its chemical structure is:

Each CARNITOR® (levocarnitine) Tablet contains 330 mg of levocarnitine and the inactive ingredients magnesium stearate, microcrystalline cellulose and povidone.

Each 118 mL container of CARNITOR® (levocarnitine) Oral Solution contains 1 g of levocarnitine/10 mL. Also contains: Artificial Cherry Flavor, D,L-Malic Acid, Purified Water, Sucrose Syrup. Methylparaben NF and Propylparaben NF are added as preservatives. The pH is approximately 5.

CLINICAL PHARMACOLOGY
CARNITOR® (levocarnitine) is a naturally occurring substance required in mammalian energy metabolism. It has been shown to facilitate long-chain fatty acid entry into cellular mitochondria, thereby delivering substrate for oxidation and subsequent energy production. Fatty acids are utilized as an energy substrate in all tissues except the brain. In skeletal and cardiac muscle, fatty acids are the main substrate for energy production.

Primary systemic carnitine deficiency is characterized by low concentrations of levocarnitine in plasma, RBC, and/or tissues. It has not been possible to determine which symptoms are due to carnitine deficiency and which are due to an underlying organic acidemia, as symptoms of both abnormalities may be expected to improve with CARNITOR®. The literature reports that carnitine can promote the excretion of excess organic or fatty acids in patients with defects in fatty acid metabolism and/or specific organic acidopathies that bioaccumulate acylCoA esters. 1-6

Secondary carnitine deficiency can be a consequence of inborn errors of metabolism. CARNITOR® may alleviate the metabolic abnormalities of patients with inborn errors that result in accumulation of toxic organic acids. Conditions for which this effect has been demonstrated are: glutaric aciduria II, methyl malonic aciduria, propionic acidemia, and medium chain fatty acylCoA dehydrogenase deficiency. 7,8 Autointoxication occurs in these patients due to the accumulation of acylCoA compounds that disrupt intermediary metabolism. The subsequent hydrolysis of the acylCoA compound to its free acid results in acidosis which can be life-threatening. Levocarnitine clears the acylCoA compound by formation of acylcarnitine, which is quickly excreted. Carnitine deficiency is defined biochemically as abnormally low plasma concentrations of free carnitine, less than 20 µmol/L at one week post term and may be associated with low tissue and/or urine concentrations. Further, this condition may be associated with a plasma concentration ratio of acylcarnitine/levocarnitine greater than 0.4 or abnormally elevated concentrations of acylcarnitine in the urine. In premature infants and newborns, secondary deficiency is defined as plasma levocarnitine concentrations below age-related normal concentrations.

PHARMACOKINETICS
In a relative bioavailability study in 15 healthy adult male volunteers, CARNITOR® Tablets were found to be bio-equivalent to CARNITOR® Oral Solution. Following 4 days of dosing with 6 tablets of CARNITOR® 330 mg b.i.d. or 2 g of CARNITOR® oral solution b.i.d., the maximum plasma concentration (C max ) was about 80 µmol/L and the time to maximum plasma concentration (T max ) occurred at 3.3 hours.

The plasma concentration profiles of levocarnitine after a slow 3 minute intravenous bolus dose of 20 mg/kg of CARNITOR® were described by a two-compartment model. Following a single i.v. administration, approximately 76% of the levocarnitine dose was excreted in the urine during the 0-24h interval. Using plasma concentrations uncorrected for endogenous levocarnitine, the mean distribution half life was 0.585 hours and the mean apparent terminal elimination half life was 17.4 hours.

The absolute bioavailability of levocarnitine from the two oral formulations of CARNITOR®, calculated after correction for circulating endogenous plasma concentrations of levocarnitine, was 15.1 ± 5.3% for CARNITOR® Tablets and 15.9 ± 4.9% for CARNITOR® Oral Solution.

Total body clearance of levocarnitine (Dose/AUC including endogenous baseline concentrations) was a mean of 4.00 L/h.

Levocarnitine was not bound to plasma protein or albumin when tested at any concentration or with any species including the human. 9

METABOLISM AND EXCRETION
In a pharmacokinetic study where five normal adult male volunteers received an oral dose of [ 3 H-methyl]-L-carnitine following 15 days of a high carnitine diet and additional carnitine supplement, 58 to 65% of the administered radioactive dose was recovered in the urine and feces in 5 to 11 days. Maximum concentration of [ 3 H-methyl]-L-carnitine in serum occurred from 2.0 to 4.5 hr after drug administration. Major metabolites found were trimethylamine N-oxide, primarily in urine (8% to 49% of the administered dose) and [ 3 H]-(gamma)-butyrobetaine, primarily in feces (0.44% to 45% of the administered dose). Urinary excretion of levocarnitine was about 4 to 8% of the dose. Fecal excretion of total carnitine was less than 1% of the administered dose. 10

After attainment of steady state following 4 days of oral administration of CARNITOR® Tablets (1980 mg q12h) or Oral Solution (2000 mg q12h) to 15 healthy male volunteers, the mean urinary excretion of levocarnitine during a single dosing interval (12h) was about 9% of the orally administered dose (uncorrected for endogenous urinary excretion).

INDICATIONS AND USAGE
CARNITOR® (levocarnitine) is indicated in the treatment of primary systemic carnitine deficiency. In the reported cases, the clinical presentation consisted of recurrent episodes of Reye-like encephalopathy, hypoketotic hypoglycemia, and/or cardiomyopathy. Associated symptoms included hypotonia, muscle weakness and failure to thrive. A diagnosis of primary carnitine deficiency requires that serum, red cell and/or tissue carnitine levels be low and that the patient does not have a primary defect in fatty acid or organic acid oxidation (see Clinical Pharmacology ). In some patients, particularly those presenting with cardiomyopathy, carnitine supplementation rapidly alleviated signs and symptoms. Treatment should include, in addition to carnitine, supportive and other therapy as indicated by the condition of the patient.

CARNITOR® (levocarnitine) is also indicated for acute and chronic treatment of patients with an inborn error of metabolism which results in a secondary carnitine deficiency.

CONTRAINDICATIONS
None known.

WARNINGS
None.

PRECAUTIONS
General
CARNITOR® (levocarnitine) Oral Solution is for oral/internal use only.

Not for parenteral use.

Gastrointestinal reactions may result from a too rapid consumption of carnitine. CARNITOR® (levocarnitine) Oral Solution may be consumed alone, or dissolved in drinks or other liquid foods to reduce taste fatigue. It should be consumed slowly and doses should be spaced evenly throughout the day to maximize tolerance.

The safety and efficacy of oral levocarnitine has not been evaluated in patients with renal insufficiency. Chronic administration of high doses of oral levocarnitine in patients with severely compromised renal function or in ESRD patients on dialysis may result in accumulation of the potentially toxic metabolites, trimethylamine (TMA) and trimethylamine-N-oxide (TMAO), since these metabolites are normally excreted in the urine.

Carcinogenesis, mutagenesis, impairment of fertility
Mutagenicity tests performed in Salmonella typhimurium, Saccharomyces cerevisiae, and Schizosaccharomyces pombe indicate that levocarnitine is not mutagenic. No long-term animal studies have been performed to evaluate the carcinogenic potential of levocarnitine.

Pregnancy
Pregnancy Category B.
Reproductive studies have been performed in rats and rabbits at doses up to 3.8 times the human dose on the basis of surface area and have revealed no evidence of impaired fertility or harm to the fetus due to CARNITOR®. There are, however, no adequate and well controlled studies in pregnant women.

Because animal reproduction studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed.

Nursing Mothers
Levocarnitine supplementation in nursing mothers has not been specifically studied.

Studies in dairy cows indicate that the concentration of levocarnitine in milk is increased following exogenous administration of levocarnitine. In nursing mothers receiving levocarnitine, any risks to the child of excess carnitine intake need to be weighed against the benefits of levocarnitine supplementation to the mother. Consideration may be given to discontinuation of nursing or of levocarnitine treatment.

Pediatric Use
See Dosage and Administration .

ADVERSE REACTIONS
Various mild gastrointestinal complaints have been reported during the long-term administration of oral L- or D,L-carnitine; these include transient nausea and vomiting, abdominal cramps, and diarrhea. Mild myasthenia has been described only in uremic patients receiving D,L-carnitine. Gastrointestinal adverse reactions with CARNITOR® (levocarnitine) Oral Solution dissolved in liquids might be avoided by a slow consumption of the solution or by a greater dilution. Decreasing the dosage often diminishes or eliminates drug-related patient body odor or gastrointestinal symptoms when present. Tolerance should be monitored very closely during the first week of administration, and after any dosage increases.

Seizures have been reported to occur in patients with or without pre-existing seizure activity receiving either oral or intravenous levocarnitine. In patients with pre-existing seizure activity, an increase in seizure frequency and/or severity has been reported.

OVERDOSAGE
There have been no reports of toxicity from levocarnitine overdosage. Levocarnitine is easily removed from plasma by dialysis. The intravenous LD 50 of levocarnitine in rats is 5.4 g/kg and the oral LD 50 of levocarnitine in mice is 19.2 g/kg. Large doses of levocarnitine may cause diarrhea.

DOSAGE AND ADMINISTRATION
CARNITOR® (levocarnitine) Tablets.

Adults: The recommended oral dosage for adults is 990 mg two or three times a day using the 330 mg tablets, depending on clinical response.

Infants and children: The recommended oral dosage for infants and children is between 50 and 100 mg/kg/day in divided doses, with a maximum of 3 g/day. Dosage should begin at 50 mg/kg/day. The exact dosage will depend on clinical response.

Monitoring should include periodic blood chemistries, vital signs, plasma carnitine concentrations and overall clinical condition.

CARNITOR® (levocarnitine) Oral Solution.

For oral use only. Not for parenteral use.

Adults: The recommended dosage of levocarnitine is 1 to 3 g/day for a 50 kg subject, which is equivalent to 10 to 30 mL/day of CARNITOR® (levocarnitine) Oral Solution. Higher doses should be administered only with caution and only where clinical and biochemical considerations make it seem likely that higher doses will be of benefit. Dosage should start at 1 g/day, (10 mL/day), and be increased slowly while assessing tolerance and therapeutic response. Monitoring should include periodic blood chemistries, vital signs, plasma carnitine concentrations, and overall clinical condition.

Infants and children: The recommended dosage of levocarnitine is 50 to 100 mg/kg/day which is equivalent to 0.5 mL/kg/day CARNITOR® (levocarnitine) Oral Solution. Higher doses should be administered only with caution and only where clinical and biochemical considerations make it seem likely that higher doses will be of benefit. Dosage should start at 50 mg/kg/day, and be increased slowly to a maximum of 3 g/day (30 mL/day) while assessing tolerance and therapeutic response. Monitoring should include periodic blood chemistries, vital signs, plasma carnitine concentrations, and overall clinical condition.

CARNITOR® (levocarnitine) Oral Solution may be consumed alone or dissolved in drink or other liquid food. Doses should be spaced evenly throughout the day (every three or four hours) preferably during or following meals and should be consumed slowly in order to maximize tolerance.

HOW SUPPLIED
CARNITOR® (levocarnitine) Tablets are supplied as 330 mg tablets embossed with "CARNITOR ST" in individual blisters, packaged in boxes of 90 (NDC 54482-144-07). Store at controlled room temperature (25°C). See USP.

CARNITOR® (levocarnitine) Tablets are manufactured for Sigma-Tau Pharmaceuticals, Inc. by Sigma-Tau S.p.A., 00040 Pomezia (Rome), Italy.

CARNITOR® (levocarnitine) Oral Solution is supplied in 118 mL (4 FL. OZ.) multiple-unit plastic containers. The multiple-unit containers are packaged 24 per case (NDC 54482-145-08). Store at controlled room temperature (25°C). See USP. CARNITOR® (levocarnitine) Oral Solution is manufactured for Sigma-Tau Pharmaceuticals, Inc. by: Hi-Tech Pharmacal Co., Inc. Amityville, NY 11701.

CARNITOR® (levocarnitine) is also available in the following dosage forms for intravenous injection:

CARNITOR® (levocarnitine) Injection is available in 1 g per 5 mL single dose vials packaged 5 vials per carton (NDC 54482-147-01). CARNITOR® (levocarnitine) Injection 5 mL vial is manufactured for Sigma-Tau Pharmaceuticals, Inc. by Sigma-Tau S.p.A., 00040 Pomezia (Rome), Italy or Chesapeake Biological Laboratories, Inc. Baltimore, MD 21230-2591.

Rx only.

REFERENCES

Bohmer, T., Rydning, A. and Solberg, H.E. 1974. Carnitine levels in human serum in health and disease. Clin. Chim. Acta 57:55-61.
Brooks, H., Goldberg, L., Holland, R. et al. 1977. Carnitine-induced effects on cardiac and peripheral hemodynamics. J. Clin. Pharmacol. 17:561-568.
Christiansen, R., Bremer, J. 1976. Active transport of butyrobetaine and carnitine into isolated liver cells. Biochim. Biophys. Acta 448:562-577.
Lindstedt, S. and Lindstedt, G. 1961. Distribution and excretion of carnitine in the rat. Acta Chem. Scand . 15:701-702.
Rebouche, C.J. and Engel, A.G. 1983. Carnitine metabolism and deficiency syndromes. Mayo Clin. Proc. 58:533-540.
Rebouche, C.J. and Paulson, D.J. 1986. Carnitine metabolism and function in humans. Ann. Rev. Nutr. 6:41-66.
Scriver, C.R., Beaudet, A.L., Sly, W.S. and Valle, D. 1989. The Metabolic Basis of Inherited Disease. New York: McGraw-Hill.
Schaub, J., Van Hoof, F. and Vis, H.L. 1991. Inborn Errors of Metabolism. New York: Raven Press.
Marzo, A., Arrigoni Martelli, E., Mancinelli, A., Cardace, G., Corbelletta, C., Bassani, E. and Solbiati, M.1991. Protein binding of L-carnitine family components. Eur. J. Drug Met. Pharmacokin., Special Issue III: 364-368.
Rebouche, C.J. 1991. Quantitative estimation of absorption and degradation of a carnitine supplement by human adults. Metabolism 40:1305-1310.

sigma-tau

Pharmaceuticals, Inc.

Gaithersburg, MD 20877

PREVIOUS EDITION IS OBSOLETE

Date of Issue: 03/04 OPI-6
【原产地英文商品名】
CARNITOR 1g/5ml/vial 5vials/box
【原产地英文药品名】
LEVOCARNITINE
【中文参考商品译名】
CARNITOR 1克/5毫升/瓶 5瓶/盒
【中文参考药品译名】
左卡尼汀
【生产厂家中文参考译名】
SIGMA TAU
【生产厂家英文名】
SIGMA TAU